1. Field
The invention is in the field of kidney dialysis procedures and includes both method and devices.
2. State of the Art
The above-indicated field in the medical treatment of patients suffering from kidney problems has existed for many years. It is standard practice to use a dialysis machine equipped with a blood pump and carrying a so-called "extracorporeal blood circuit" for passing arterial blood drawn from the body of a patient through the dialysis unit and for returning the blood as dialyzed back to the venous system of the patient body of the patient. Both the drawing of the arterial blood and the insertion of the dialyzed blood into the venous system of the body may be accomplished by the use of tubular, dialysis access devices separate from the extracorporeal blood circuit.
One type of separate access device, often referred to as an A-V hemodialysis device, is known in the art as an AVF or an AVG dialysis set. Such a set is equipped with a special, large bore, dialysis needle for insertion into a specially provided artery/vein fistula (AVF) or artery/vein graft (AVG) of the patient's body and with a single, relatively short, blood-flow tube, to one end of which the dialysis needle is attached. The opposite end of this blood-flow tube is adapted for attachment to an open end of the extracorporeal blood circuit tubing of the dialysis machine. Thus, such an access device is normally used for temporary vascular access to the arterial system of a dialysis patient leading from the heart and for temporary vascular access to the venous system of the patient leading to the heart.
An A-V fistula is a patient's specially joined artery and vein into which special, large bone dialysis needles are inserted. An A-V graft joins an artery and vein of the patient by means of a short, interconnecting, blood-flow tube. Either of these special vascular access provisions may be made in the patient's body prior to the dialysis regimen, depending on circumstances.
The blood-flow tube of the AVF or AVG hemodialysis set is relatively short, about one foot in length, compared to the length of the extracorporeal blood circuit tubing, which is several feet in length. The extracorporeal tubing of the typical dialysis machine is equipped with flow shut-off clamps and so-called injection/administration port structures. These are usually positioned in respective, opposite end portions of the extracorporeal blood circuit tubing at the arterial and the venous sides, respectively, of the machine. Typically, utilitarian units additional to the dialysis unit, such as a venous drip chamber, a heparin infusion line, a connection for an IV saline solution bag, and arterial and venous pressure monitors, are provided in the extracorporeal blood circuit tubing of the machine.
The hemodialysis access devices are normally removed when the dialysis has been completed for the particular appointed treatment and after blood specimens have been withdrawn and any necessary or desirable drugs or other additions have been introduced into the patient's body through the injection/administration ports in the extracorporeal tubing of the dialysis machine. This has been routine procedure for the many years we have worked as a dialysis technician and a supervisory nurse, respectively, in kidney dialysis clinics..
It often happens, however, that introduction of the necessary and very expensive drugs is not effective for one reason or another, e.g. because of the overall length of blood-flow tubing leading from the dialysis unit to the patient and the tendency for drugs to be dissipated in the long travel through such tubing considering the usual placement of the injection/administration ports in the extracorporeal blood circuit of the machine. In such instances, we have attached a syringe to the inflow end of the blood-flow tube of the AVF or AVG hemodialysis set that has been removed from the machine but that is still emplaced in the body of the patient and have added a necessary or desired drug to the saline solution for introduction into the patient. Others in the field concerned may possibly have done and are continuing to do the same, but this is unsatisfactory because the introduction of different drugs at different times means that the syringe has to be repeatedly removed, emptied, sterilized, refilled with fresh saline solution and a different drug, and reattached. This necessitates repeated sterilizations of components or the use of several syringes that have been pre-prepared with respective quantities of saline solution and with respective drugs that must be independently introduced into the patient. This is also unsatisfactory because it allows the possible introduction of airborne contaminants into the patient or into blood from the patient, thereby contaminating the area.
Similar difficulties have existed with a different type of access device used in kidney dialysis and known as a "subclavian catheter" or a "central venous catheter", i.e., a "CVC". Such device is specially made for hemodialysis use by being provided with an elongate, dual lumen, needle-like, catheter dialysis portion for emplacement in the patient after a usual puncturing needle has prepared the way for such an emplacement in a subclavian vein or in a central vein of the body of a patient following penetration of the vein by such usual puncturing needle. Such a dialysis catheter has, as a patient access dialysis set, two relatively short tubes leading to the dual lumens, respectively, of the needle-like dialysis catheter portion.